Structural diversity and oligomerization of bacterial ubiquitin-like proteins.
Gong, M., Ye, Q., Gu, Y., Chambers, L.R., Bobkov, A.A., Arakawa, N.K., Matyszewski, M., Corbett, K.D.(2025) Structure 33: 1016-1026.e4
- PubMed: 40250427 
- DOI: https://doi.org/10.1016/j.str.2025.03.011
- Primary Citation of Related Structures:  
8U38, 9CD2, 9D59, 9D5A, 9D5B - PubMed Abstract: 
Bacteria possess a variety of operons with homology to eukaryotic ubiquitination pathways that encode predicted E1, E2, E3, deubiquitinase, and ubiquitin-like proteins. Some of these pathways have recently been shown to function in anti-bacteriophage immunity, but the biological functions of others remain unknown. Here, we show that ubiquitin-like proteins in two bacterial operon families show surprising architectural diversity, possessing one to three β-grasp domains preceded by diverse N-terminal domains. We find that a large group of bacterial ubiquitin-like proteins possess three β-grasp domains and form homodimers and helical filaments mediated by conserved Ca 2+ ion binding sites. Our findings highlight a distinctive mode of self-assembly for ubiquitin-like proteins and suggest that Ca 2+ -mediated ubiquitin-like protein filament assembly and/or disassembly enables cells to sense and respond to stress conditions that alter intracellular metal ion concentration.
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
Organizational Affiliation: 

















